The present invention relates to material handling devices and more particularly to a device for use in a foundry for handling molds or the like.
In the operation of a foundry an article such as a mold or sandcake is prepared into which molten metal is poured. Frequently, it is necessary to move such an article from one location to another. In addition it may be necessary to invert the article so that it rests on what was formerly its top surface. Consequently, a crane, a hoist or other similar apparatus is equipped with a handling device which engages opposite sides of the article to lift and move it from one location to another. Such devices for use in a foundry are well known.
One such mold handling device utilizes a pair of parallel moving gripper arms to engage opposite sides of a mold or sandcake. The gripper pads which contact the mold are rotatably mounted on antifriction bearings. This permits the mold to be rolled over to an inverted position while it is being lifted by the device.
The gripper arms of the known mold handling device must be kept parallel in order to maintain the gripper pads in coaxial alignment. If the gripper pads are not in coaxial alignment, the mold or other article can not be inverted while it is being lifted in the device.
Further, difficulties have been encountered in maintaining the center of gravity of the mold or other article in line with the cable which supports the mold handling device. If the load is not centered under the cable, the mold handling device may tilt dangerously, possibly injuring the workman or damaging the mold. In a known mold handling device a mechanical linkage is utilized to maintain the gripping arms equidistant from the center line of the cable which supports the device.